Semiconductor die for such applications as low voltage MOSFETs, IGBTs or integrated circuits (ICs) would benefit if formed in an ultrathin wafer, for example a wafer thinner than 50 micrometers and down, for example, to 5 microns. These substrates or die could offer advantages of lower RDSON, higher switching speed and improved device ruggedness. High performance microprocessors or ICS would also benefit from improved heat dissipation to the die bottom surface.
However, it is very difficult to thin down the parent wafer for the die to below about 50 micrometers and complete its processing, such as backside metallizing, inspections, probing and assembly. Indeed is currently not even possible to complete and process wafers as thin as 5 to 15 micrometers.